kiṃsuka : [m.] the tree Butea Frondosa.

A.P. Buddhadatta Mahathera, Concise Pali-English and English-Pali Dictionary [available as digital version from Metta Net, Sri Lanka]

Kiŋsuka [kiŋ+su+ka] N. of a tree (creeper), lit. "what- ever -- like," or "what do you call it," i. e. strange tree (see kiŋ su & kiŋ 3), pop. name for the Butea frondosa S iv.193 (parable of the k.); J ii.265 (˚opama -- jātaka); v.405; vi.536. Perhaps v. l. at SnA 284.
   -- puppha the (red) flower of the k. tree Vism 252. -- vaṇṇa of the colour of the k. (flower) J i.73 (angārā ashes).

Pali-English Dictionary, TW Rhys Davids, William Stede,